Marcus Aurelius
Meditations 10.35
The healthy eye ought to see all visible things and not to say, I wish for green things; for this is the condition of a diseased eye. And the healthy hearing and smelling ought to be ready to perceive all that can be heard and smelled. And the healthy stomach ought to be with respect to all food just as the mill with respect to all things which it is formed to grind. And accordingly the healthy understanding ought to be prepared for everything which happens; but that which says, Let my dear children live, and let all men praise whatever I may do, is an eye which seeks for green things, or teeth which seek for soft things.
Marcus Aurelius, Meditations 10.35, translated by George Long
The sound eye should see all there is to be seen, but should not say: I want what is green only. For that is characteristic of a disordered eye. And the sound hearing and smell should be equipped for all that is to be heard or smelled. And the sound digestion should act towards all nutriment as a mill towards the grist which it was formed to grind. So should the sound mind be ready for all that befalls. But the mind that says: Let my children be safe! Let all applaud my every act! is but as an eye that looks for green things or as teeth that look for soft things.
Marcus Aurelius, Meditations 10.35, translated by C. R. Haines